tonight one of the most wanted men in the world the leader of the taliban in pakistan, a $5 million bounty on his head, now dead. Killed by a u.S. Drone. His young looks in stark contrast to his crimes. The master mind to that grisly plot portrayed in the movie zero dark thirty. U.S. Officials saying we got him. Chief investigative correspondent brian ross tonight. Reporter: For the cia getting hakimullah mehsud was personal. He was considered a master mind in the attack that killed seven cia officers and an afghan outpost in 2009 as portrayed in the movie zero dark thirty. Mehsud gloated over the cia deaths and released a video he made with the suicide bomber used in the attack. This was an important strike. It kills the leader of an organization, that is a major threat to the united states. But he will be replaced. Reporter: Only in his mid30s, he was mehsud who led the pakistan taliban to expand its reach to america. The foiled bombing in new york's times square in 2010 was organized by mehsud. The bomber, faisal shahzad of connecticut trained with mehsud and appeared in this video denouncing the u.S. In the last few weeks, mehsud appeared on the bbc, saying he was open to peace talks, but would continue to try to kill americans. The u.S. Got him first. Some u.S. Officials say killing mehsud with the drone attack is the most significant victory against terrorism since the death of osama bin laden. As one of them told my colleague martha raddatz today's, it's a good day. Brian, thank you. We're going to turn to the

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